package com.hmdp.utils;

import lombok.RequiredArgsConstructor;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
@RequiredArgsConstructor
public class RedisIdWork {
    /**
     * 开始时间戳
     * 指定了ZoneOffset.UTC时区
     */
    private static final long BEGIN_TIMESTAMP = LocalDateTime.of(2025, 1, 1, 0, 0, 0)
            .toEpochSecond(ZoneOffset.UTC);

    //序列号位数
    private static final int COUNT_BITS = 32;
    private final StringRedisTemplate stringRedisTemplate;

    public long nextId(String keyPrefix){
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;
        //2.生成序列号
        //2.1 获取当前日期，精确到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        //2.2 自增长
        Long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);
        //3. 拼接并返回
        return timestamp << COUNT_BITS | count;
    }
}
